JPH1151170A - Gear change ratio controller of continuously variable transmission - Google Patents

Abstract

PROBLEM TO BE SOLVED: To smoothly perform foot return up shift in addition to auto up shift and foot leave up shift by changing dynamic characteristics in accordance with gear change mode at the time of up shift. SOLUTION: Driving torque input from an engine is input into a continuously variable transmission 17 through a torque converter 12 and is transmitted to a secondary pulley 26 through a V belt 24 from a primary pulley 16. When power is transmitted, a movable conical plate 22 of the primary pulley 16 and a movable conical plate 34 of the secondary pulley 26 are displaced to the axial direction to change a gear change ratio continuously. A gear change ratio of the continuously variable transmission 17 and contact friction of the V belt 24 are controlled by a hydraulic control valve 3. Furthermore, a line pressure control means which adjusts line pressure and a step motor 64 which drives a gear change control valve in accordance with a target gear change ratio from a CVT control unit 1 are stored and mounted. The CVT control unit 1 reads signals which indicate various driving conditions and controls a gear change ratio variably in accordance with demands of a vehicle and a driver.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an improvement in a speed ratio control device for a continuously variable transmission.

[0002]

2. Description of the Related Art In a speed ratio control apparatus for a continuously variable transmission mounted on a vehicle, a target speed ratio is determined from a vehicle speed and a throttle opening TVO (or an accelerator pedal depression amount). As shown in FIG. 10A, a driving operation in which the accelerator pedal is released from an arbitrary position during traveling, and a substantially constant depression amount (for example, FIG. 11) after the accelerator pedal is depressed for start acceleration. In the driving operation in which the vehicle speed is increased while maintaining the TVO (6/8 of the broken line A shown in FIG. 5), the upshift is performed according to the previously set shift map, and the shift direction is the same, but the shift condition is different. , Lift the former upshift (Fig. 11
B), the latter is automatically upshifted (broken line A in FIG. 11).
And

As such a gear ratio control device, for example, Japanese Patent Application Laid-Open No. Hei 8-74958 is known, and the throttle opening TVO (or accelerator pedal depression amount) and the attained gear ratio (control target gear ratio) are known. The above two upshift modes are determined from the change amount of the speed change, and the response speed of the actual speed ratio is changed for each speed change mode, thereby obtaining a speed ratio response suitable for each speed change mode having different speed change conditions. Thus, it is possible to reduce shift shock and fuel consumption.

[0004]

By the way, in a foot release upshift in which the upshift is performed as a result of releasing the accelerator pedal during traveling, the throttle opening TVO = 0/8 and the target speed ratio is almost the highest Hi side. , And the vehicle speed gradually decreases. However, as shown in FIG. 10 (C) and FIG. 11 (C), even when the depression amount is reduced from the state in which the accelerator pedal is depressed, the throttle opening TVO can be set to an arbitrary value. When the throttle opening TVO and the amount of change in the attained gear ratio exceed a predetermined threshold value, the upshift is performed, and the upshift is not performed because the throttle opening TVO is not fully closed. The vehicle speed is a value corresponding to the throttle opening TVO, for example, the speed is increased, and this shift is distinguished from the above-mentioned foot-off upshift as a foot-return upshift.

However, in the above-described conventional gear ratio control device, when the depression amount is reduced from the state in which the accelerator pedal is depressed, a distinction is not made between a foot-return upshift and a foot-release upshift. When the speed ratio change (the target speed ratio in FIG. 10) is set gently so as to satisfy the speed change performance, when the foot release upshift is performed, the speed change is too slow and the foot is released from the accelerator pedal. Regardless, the decrease in the engine speed is delayed, which gives the driver a sense of incongruity. Then, the problem is that the gear shift is too fast, giving the uncomfortable feeling that the vehicle accelerates even though the accelerator pedal is released. Was Tsu.

[0006] Further, by setting a large threshold value for the amount of change in the throttle opening TVO and the attained gear ratio, it is possible to delay the determination of an upshift due to a change in the throttle opening TVO. Instead of a foot-return upshift, an auto-upshift is performed in response to an increase in vehicle speed.The auto-upshift is set so that the engine speed does not increase, so the speed ratio change speed is set to a large value. In this case, there is a problem that the speed is too fast in such a return-to-foot speed change, and the driver feels uncomfortable as if the vehicle is accelerated despite the accelerator pedal being returned in the same manner as described above.

The present invention has been made in view of the above-mentioned problems, and has as its object to smoothly perform a foot return upshift in addition to an automatic upshift and a foot release upshift.

[0008]

According to a first aspect of the present invention, there is provided a driving state detecting means for detecting a driving state based on at least a vehicle speed and an amount of depression of an accelerator pedal, and a final shift of a continuously variable transmission according to the driving state. Reaching speed ratio setting means for setting the reaching speed ratio as a target value of the ratio, actual speed ratio detecting means for detecting the actual speed ratio, and target speed ratio setting means for calculating the target speed ratio according to predetermined dynamic characteristics A speed ratio deviation for calculating a deviation between the attained speed ratio and the target speed ratio in the continuously variable transmission speed ratio control device for setting the actual speed ratio to the attained speed ratio while following the target speed ratio. Arithmetic means;
Opening calculation means for calculating the opening of the accelerator pedal,
An input shaft rotation speed change amount calculating means for calculating a change amount of the input shaft rotation speed of the continuously variable transmission; and an upshift shift mode based on the speed ratio deviation, the accelerator pedal opening, and the input shaft rotation speed change amount, Shift mode determining means for determining any one of an automatic upshift, a foot release upshift, and a foot return upshift, wherein the target gear ratio setting means determines the dynamic characteristic according to the shift mode at the time of these upshifts. To change.

According to a second aspect of the present invention, in the first aspect, the shift mode determining means includes, in addition to the shift ratio deviation, the accelerator pedal opening and the change amount of the input shaft speed, a shift mode of a previous shift mode. Depending on the determination result, the upshift gear mode is set to auto upshift, foot upshift,
It is determined to be one of the foot return upshifts.

In a third aspect based on the first aspect, the target speed ratio setting means is preset in accordance with each of the shift modes of an auto upshift, a foot release upshift, and a foot return upshift. A dynamic characteristic calculating means for changing the dynamic characteristic based on the dynamic characteristic map is provided.

In a fourth aspect based on the third aspect, the dynamic characteristic calculating means calculates a dynamic characteristic based on the speed ratio deviation.

In a fifth aspect based on the first aspect, the target speed ratio setting means is characterized in that a response speed of the target speed ratio to the attained speed ratio is large when an automatic upshift is performed, and Small when
At the time of a foot release upshift, the value is set to a value between the auto upshift and the foot return upshift.

[0013]

Therefore, the first aspect of the present invention is to change the shift mode of the upshift based on the change ratio of the gear ratio, the degree of opening of the accelerator pedal and the amount of change in the input shaft speed, to the auto-upshift, the foot-off upshift, the foot-return upshift And then setting the dynamic characteristic according to each shift mode, it is possible to obtain a dynamic characteristic = shift response according to the driving state of each upshift. By setting the characteristic constant to be small, the dynamic characteristic constant to be large when the foot is upshifted, and the dynamic characteristic constant to be even larger than the upshift when the foot is upshifted, the shift response (gear speed) is faster during the auto upshift. To prevent a delay in the actual gear ratio, and when the foot is upshifted, the target response is slowed down and the actual gear ratio is gradually changed, resulting in acceleration. The shift shock can be prevented by shortening the time, and the target response is further slowed down when the foot is upshifted, the actual gear ratio is released, and the accelerator pedal is returned more slowly than during the upshift. In such a case, an uncomfortable feeling such as acceleration of the vehicle can be reliably prevented, and the drivability of the vehicle including the continuously variable transmission can be improved.

Further, the second invention determines the upshift shift mode in accordance with the previous shift mode determination result in addition to the speed ratio deviation, the accelerator pedal opening, and the change amount of the input shaft speed. It is possible to accurately determine an auto upshift, a foot release upshift, and a foot return upshift.

The third aspect of the present invention is to calculate a dynamic characteristic by calculating a dynamic characteristic based on a dynamic characteristic map set in advance according to each of the shift modes of an auto upshift, a foot release upshift, and a foot return upshift. Optimal dynamic characteristics can be set for each upshift mode while calculating characteristics quickly.

According to the fourth aspect of the present invention, when calculating the dynamic characteristics, the dynamic characteristics are calculated based on the speed ratio deviation. Therefore, the dynamic characteristics of each upshift mode are variably controlled in accordance with the driving state. Therefore, it is possible to set an optimum dynamic characteristic according to the operating state.

According to a fifth aspect of the present invention, the upshift speed change mode includes an auto upshift, a foot release upshift,
In addition to the three types of foot return upshifts, the response speed is increased during an auto upshift to prevent a delay in the actual gear ratio, while the response speed is slowed during a foot upshift to gradually change the actual gear ratio. Thus, it is possible to prevent the shift shock by reducing the time during which the acceleration occurs, and to further reduce the response speed at the time of the foot return upshift to change the actual speed ratio more slowly than at the time of the upshift by releasing the foot. Discomfort that the vehicle accelerates when the accelerator pedal is released can be reliably prevented.

[0018]

Embodiments of the present invention will be described below with reference to the accompanying drawings.

1 to 9 show an embodiment of the present invention.
FIG. 1 is a schematic configuration diagram of a gear ratio control device of a V-belt type continuously variable transmission, FIG. 2 is a schematic configuration diagram of a hydraulic control valve 3, and FIG. 3 is a conceptual diagram of control performed by a CVT control unit 1. Shown respectively.

In FIG. 1, a continuously variable transmission 17 is connected to an engine (not shown) via a torque converter 12 having a lock-up clutch 11, and includes a primary pulley 16 on the input shaft side as a pair of variable pulleys, and a drive. A secondary pulley 26 connected to a shaft (output shaft);
The pair of variable pulleys 16 and 26 are connected by a V-belt 24.

The primary pulley 16 has a fixed conical plate 18 which rotates integrally with the output shaft of the torque converter 12.
And a V-shaped pulley groove formed opposite to the fixed conical plate 18 and a primary pulley cylinder chamber 20.
The movable conical plate 22 is capable of being displaced in the axial direction by a hydraulic pressure acting on the main body (primary pulley hydraulic pressure).

On the other hand, the secondary pulley 26 is provided on the output shaft side, and has a fixed conical plate 30 that rotates integrally with the output shaft, and a V-shaped pulley groove that is disposed to face the fixed conical plate 30. And a movable conical plate 34 that can be displaced in the axial direction according to the hydraulic pressure acting on the secondary pulley cylinder chamber 32 (secondary hydraulic pressure). The primary pulley cylinder chamber 20 has a larger pressure receiving area than the secondary pulley cylinder chamber 32.

The drive torque input from the engine is input to the continuously variable transmission 17 via the torque converter 12 and transmitted from the primary pulley 16 to the secondary pulley 26 via the V-belt 24.

At the time of power transmission as described above, the movable conical plate 22 of the primary pulley 16 and the secondary pulley 26
Is displaced in the axial direction, and the V-belt 24
By changing the contact radius with the pulley, the gear ratio between the primary pulley 16 and the secondary pulley 26, that is, the gear ratio ip can be continuously changed.

For example, if the width of the V-shaped pulley groove of the primary pulley 16 is reduced, the contact radius between the secondary pulley 26 and the V-belt 24 is reduced. And 34 are displaced in the opposite direction, the gear ratio changes to the Lo side and is set to a large value.

The gear ratio of the continuously variable transmission 17 and the contact frictional force of the V-belt 24 are controlled by a hydraulic control valve 3, and the hydraulic control valve 3 includes a line pressure control means (not shown) for adjusting the line pressure. As shown in FIG. 2, a step motor 6 for driving the shift control valve 63 in accordance with the target shift ratio from the CVT control unit 1
4 is installed.

The CVT control unit 1 includes a primary pulley rotation speed sensor 6 for detecting the rotation speed Npri (input shaft rotation speed) of the primary pulley 16 of the continuously variable transmission 17, and a rotation speed Nsec (output shaft rotation speed) of the secondary pulley 26. ), The signal from the secondary pulley rotation speed sensor 7, the shift position from the inhibitor switch 8,
Throttle opening TVO from throttle opening sensor 5 according to the amount of depression of the accelerator pedal operated by the driver
(Or an accelerator pedal opening) and other signals from operating state detecting means, as well as an engine speed Ne (not shown) and a signal indicating an operating state such as an idle switch (not shown). The gear ratio is variably controlled according to the driver's request. In addition,
In the present embodiment, a value obtained by multiplying the secondary rotation speed Nsec by a predetermined constant is used as the vehicle speed VSP.

The speed ratio control for changing the widths of the V-shaped pulley grooves of the primary pulley 16 and the secondary pulley 26 is performed by controlling the hydraulic pressure to the primary pulley cylinder chamber 20, and as shown in FIG. This is performed by controlling a step motor 64 that drives a shift control valve 63 of the hydraulic control valve 3.

The stepping motor 64 drives the transmission control valve 63 in response to a command from the CVT controller 1 via the transmission link 67, and adjusts the hydraulic pressure supplied to the cylinder chamber 20 of the primary pulley 16 to change the actual transmission. Ratio ip _R
The controls to match the target speed ratio ip _T.

The feedback means mainly composed of the hydraulic control valve 3 and the speed change link 67 is constructed in the same manner as in the conventional example, and the step motor 64 is connected to the pinion 6.
6 and the rack 65 meshes with each other.
Is connected to one end of a transmission link 67 having a predetermined lever ratio. A spool (not shown) of the transmission control valve 63 is connected in the middle of the transmission link 67, and a feedback member 158 responsive to an axial displacement of the movable conical plate 22 is provided at the other end of the link 67. Be linked.

One end of the feedback member 158 is axially engaged with the outer periphery of the movable conical plate 22, and the rod 60a of the line pressure control valve 60 is connected to a predetermined position. The shift control valve 63 and the line pressure control valve 60 are driven in accordance with the displacement of the movable conical plate 22 that becomes the actual gear ratio.

The shift control valve 63 controls the hydraulic pressure supplied to the cylinder chamber 20 of the primary pulley 16 in accordance with the drive amount (rotational position) of the step motor 64, and the primary pressure is changed by the displacement of the rack 65 to the left in the drawing. The shift to the Hi side is performed by increasing the oil pressure supplied to the cylinder chamber 20 of the pulley 16, and the shift to the Lo side is performed by reducing the oil pressure of the cylinder chamber 20 by rightward displacement.

In FIG. 2, reference numeral 78 denotes a manual valve responsive to the shift lever, 76 denotes a negative pressure diaphragm,
7 is a throttle valve which responds to the negative pressure diaphragm 76,
A stopper 95 locks the rack 65 at the highest Hi and lowest Lo positions.

Next, an example of the gear ratio control performed by the CVT control unit 1 will be described in detail with reference to the control conceptual diagram of FIG.

In FIG. 3, the target speed ratio generating device 400 constituting the CVT control unit 1 calculates the vehicle speed VSP based on the secondary rotation speed Nsec from the secondary rotation speed sensor 7 and the throttle opening TVO of the throttle opening sensor 5. A target primary rotation speed calculation unit 410 for calculating a target primary rotation speed tNpri according to the operating state based on the map of FIG. 11; and a target primary rotation speed t
Ultimate speed ratio calculating unit 43 that calculates the ultimate speed ratio ip ₀ by dividing Npri by the detected secondary rotational speed Nsec.
0, and the gear ratio deviation computing unit 450 for computing a deviation eip arrival speed ratio ip ₀ and the target speed change ratio ip _T, match the actual speed ratio ipr from the gear ratio deviation eip and (Npri / Nsec) to reach speed ratio ip ₀ A target gear ratio dynamic characteristic determination unit 460 that determines a constant T ₀ of a dynamic characteristic (gear ratio response = gear speed) of a target gear ratio when the gear ratio is changed, and a dynamic characteristic of the attained gear ratio ip ₀ and the target gear ratio. the constant T ₀ in group, a de-system filters the dynamic characteristics of the speed ratio servo device 500 (transfer characteristic), in addition to the target speed ratio generator 470 for calculating a command gear ratio ipc a target speed change ratio ip _T An upshift mode determining unit 480 for determining a shift mode at the time of an upshift from the target primary rotational speed tNpri, the speed ratio deviation eip, and the throttle opening TVO is provided. Mode The dynamic characteristic constant T ₀ is determined from the corresponding map.

The speed ratio servo device 500 controls the stepping motor 6 based on the commanded speed ratio ipc from the target speed ratio generating device 400, the vehicle speed VSP and the primary speed Npri.
4 is performed.

It is to be noted that, except for the upshift mode judging section 480 in the target gear ratio generating device 400, it is almost the same as Japanese Patent Application No. 9-226656 proposed by the present applicant.

Here, the upshift mode also shown in the conventional example is divided into three shift modes, that is, an auto upshift, a foot release upshift and a foot return upshift, as shown in the following table.

[0039]

[Table 1]

Next, the case where the above-described gear ratio control is performed by the CVT control unit 1 mainly composed of a microcomputer will be described with reference to the flowchart of FIG. Note that the flowchart of FIG. 4 shows processing performed by the upshift mode determination unit 480 and the target gear ratio dynamic characteristic determination unit 460 of the target gear ratio generation device 400 of FIG. 9-2
No. 26656.

First, in step S1, a comparison is made as to whether the gear ratio deviation eip obtained by the gear ratio deviation calculator 450 is less than a preset threshold value DipT for determining a gear direction, and the difference eip is determined by a threshold. If the value is equal to or more than the value DipT, it is determined that the shift is a downshift, and the process proceeds to step S9. If not, the process proceeds to step S2 to compare whether the deviation eip is less than the negative threshold value -DipT. If the deviation eip is smaller than the negative threshold value -DipT, it is determined that a downshift has occurred, and the process proceeds to step S3. To end.

In step S3 where it is determined that the upshift is performed, the upshift of the upshift shown in Table 1 is performed based on the throttle opening TVO, the gear ratio deviation eip, the change amount ΔDrev of the target primary rotational speed tNpri, and the previous shift mode. The mode is determined as shown in FIG. judge. The change amount ΔDrev of the target primary rotation speed tNpri is calculated from the difference between the current value and the previous value of the target primary rotation speed tNpri.

The determination of the automatic shift-up, the foot-up shift-up, and the foot-return shift-up is executed based on the result of the previous shift mode determination in different cases as shown in FIG.

(1) When the previous shift mode is an auto upshift Condition 1: Throttle opening TVO ≠ 0 and change amount ΔDre
If v <K _D , the back upshift. However, K _D is a threshold for determining a foot back upshift, in which is preset to the value of K _D <0.

Condition 2: If the throttle opening TVO = 0, the upshift is performed.

If the above condition 1 or condition 2 is not satisfied, it is determined that an automatic upshift has occurred.

(2) When the previous shift mode is a foot release upshift Condition 3: If the throttle opening TVO ≠ 0 is satisfied, a foot return upshift.

Condition 4: If the deviation eip> Ke is satisfied, it is determined that an automatic upshift is performed. In addition, Ke is a threshold value for automatic upshift determination.

When the above condition 3 or condition 4 is not satisfied, it is determined that the foot is upshifted.

(3) When the previous gear change mode is a foot return upshift Condition 2: If the throttle opening TVO = 0, the foot release upshift is performed.

Condition 4: If deviation eip> Ke is satisfied, it is determined that an automatic upshift has been performed.

If the above condition 2 or condition 4 is not satisfied, it is determined that the foot is upshifted.

(4) When the previous shift mode is a downshift Condition 2: If the throttle opening TVO = 0 is established, release the upshift.

[0054] Condition 1: If the throttle opening TVO ≠ 0 and variation ΔDrev <K _D, a foot back upshift.

If the above condition 1 or condition 2 is not satisfied, it is determined that an automatic upshift has occurred.

According to the above cases (1) to (4),
If it is determined in step S2 that the shift is an upshift, as shown in FIG. 5, one of the automatic shift up, the foot release shift up, and the foot return shift up is determined based on the above conditions 1 to 4.

[0057] Then, in step S8 from step S4, in accordance with the shifting mode as shown in FIG. 6 (A) ~ (C) , the map of the target dynamic characteristic time constant T ₀ is selected, in step S10, shift The target dynamic characteristic time constant T ₀ is calculated according to the ratio deviation eip, and the process ends.

Here, each target dynamic characteristic time constant T₀about
To explain, in the case of auto upshift, FIG.
As shown in (A), regardless of the magnitude of the gear ratio deviation eip,
Target dynamic characteristic time constant T₀Is set to a small constant value and the target
Gear ratio ip_TTransmission ratio ip with respect to _RDelay is small
It is set as follows.

In the case of a foot release upshift, FIG.
As shown in (B), the target dynamic characteristic time constant T ₀ is set to increase as the speed ratio deviation eip decreases, and the actual speed ratio ip _R is maintained at a constant speed with respect to the changing ultimate speed ratio ip ₀ . It is set to follow slowly to the target speed ratio ip _T.

In the case of a foot upshift,
As shown in FIG. 6C, as the speed ratio deviation eip decreases, the target dynamic characteristic time constant T ₀ increases, and the value of the target dynamic characteristic time constant T ₀ increases as compared with the foot-off upshift. is set, a change in the actual speed ratio ip _R is set to follow the more slowly the target speed ratio ip _T than the upshift foot release.

For a downshift, a target dynamic characteristic time constant T ₀ is calculated from a downshift map (not shown).

As described above, by changing the target dynamic characteristic time constant T ₀ according to the shift mode at the time of the upshift, each upshift mode can be smoothly performed as shown in FIGS. It becomes possible.

FIG. 7 shows the case of an automatic upshift, in which the throttle opening TVO is set to a fixed value (for example, 4
/ 8). This auto upshift, from FIG. 6 (A), the order target dynamic characteristic time constant T ₀ is constant small value regardless of the speed ratio deviation eip, to reach the speed ratio ip ₀ which varies slowly, actual speed The delay of the ratio ip _R is made as small as possible, and the overshoot of the primary rotational speed Npri is prevented, so that the fuel efficiency can be improved.

Next, in the case of the upshift shown in FIG. 8, the throttle opening TVO at the vehicle speed VSP = 40 km / h.
FIG. 6B shows that the target dynamic characteristic time constant T ₀ increases as the speed ratio deviation eip decreases. since the, to reach the speed ratio ip ₀ which varies discontinuously, it is possible to the actual speed ratio ip _R follows up slowly at a constant speed. Therefore, it is possible to improve the drivability by shortening the time during which the change in the acceleration is occurring, suppressing the feeling of thrust at the time of shifting off the foot, and improving the drivability.

Further, in the case of the foot return upshift shown in FIG. 9, when the vehicle speed VSP = 40 km / h and the throttle opening TV
This shows a case where O = 8/8 is changed to 4/8,
In FIG. 6 (C), the target dynamic characteristic time constant T ₀ is set to a larger value as the speed ratio deviation eip decreases, and is set to a larger value than the foot release up shift. Achieved gear ratio ip that changes discontinuously
₀ against, the real speed ratio ip _R is change can be further follow-up more slowly than during the foot release upshift. Therefore, as in the above-described conventional example, it is possible to reliably prevent a sense of incongruity such as acceleration of the vehicle despite returning the accelerator pedal, and to smoothly perform an upshift in any situation.
This makes it possible to improve the drivability of the vehicle provided with the continuously variable transmission.

In this way, the shift mode of the upshift is
Automatic upshifts, foot release upshifts, and foot return upshifts are classified into three types, and a target dynamic characteristic time constant T ₀ based on a map corresponding to each upshift mode.
Since it made to be set, while at the time of auto up-shift to prevent delay of target response to fast (shift speed) actual speed ratio ip _R, gentle actual speed ratio ip _R and slow target response at the time of foot release upshift , The time during which the acceleration occurs can be reduced to prevent a shift shock. In addition, the target response is further slowed down in the case of a foot-return upshift, and the actual speed ratio ip _R is released from the foot. Can also be changed more gradually, so that an uncomfortable feeling such as acceleration of the vehicle when the accelerator pedal is released can be reliably prevented.

In the above-described embodiment, the case where the belt type is adopted as the continuously variable transmission has been described. However, although not shown, the same operation and effect can be obtained as a toroidal type continuously variable transmission.

[Brief description of the drawings]

FIG. 1 is a block diagram of a belt-type continuously variable transmission showing an embodiment of the present invention.

FIG. 2 is a schematic diagram of a hydraulic control valve.

FIG. 3 is a control conceptual diagram of the CVT control unit.

FIG. 4 is a flowchart illustrating an example of gear ratio control performed by a CVT control unit.

FIG. 5 is an explanatory diagram showing an upshift mode and a transition state of each mode.

FIG. 6 is a map of target dynamic characteristic constants corresponding to each upshift mode, showing a relationship between a speed ratio deviation eip and a target dynamic characteristic constant, (A) is an auto up mode, (B) is a foot release up mode, (C) shows the foot return up mode.

FIG. 7 is a graph showing a state of an upshift in an auto-up mode, and shows a relationship between respective operation states with a lapse of time.

FIG. 8 is a graph showing the state of an upshift in the foot release up mode, showing the relationship between the respective driving states over time.

FIG. 9 is also a graph showing a state of an upshift in the case of a foot return up mode, and shows a relationship between respective driving states with the passage of time.

FIG. 10 shows a conventional example, and shows a relationship between elapsed time and each operation state according to each shift mode.

FIG. 11 shows a shift map of the continuously variable transmission, and shows a target primary rotational speed tNpri according to the vehicle speed, using the throttle opening TVO as a parameter.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 CVT control unit 6 Primary rotation speed sensor 7 Secondary rotation speed sensor 16 Primary pulley 17 Continuously variable transmission 18 Fixed conical plate 20 Primary pulley cylinder room 22 Movable conical plate 24 V belt 26 Secondary pulley 30 Fixed conical plate 32 Secondary pulley cylinder room 34 Movable conical plate 63 Shift control valve 64 Step motor

Continued on the front page (51) Int.Cl. ⁶ Identification code FI F16H 59:70

Claims (5)

[Claims] An operating state detecting means for detecting an operating state based on at least a vehicle speed and an amount of depression of an accelerator pedal, and an attained gear ratio is set as a final gear ratio target value of the continuously variable transmission according to the operating state. Reaching speed ratio setting means, actual speed ratio detecting means for detecting an actual speed ratio, and target speed ratio setting means for calculating a target speed ratio in accordance with predetermined dynamic characteristics. A speed ratio control device for a continuously variable transmission that sets a target speed ratio while following a target speed ratio, wherein a speed ratio deviation calculating unit that calculates a deviation between the target speed ratio and the target speed ratio, and an opening degree of the accelerator pedal , An input shaft rotation amount change amount calculation unit for calculating the change amount of the input shaft rotation speed of the continuously variable transmission, and a change in the gear ratio deviation and the accelerator pedal opening and the input shaft rotation speed. Up from quantity A shift mode determining means for determining a shift speed mode to be any of an auto upshift, a foot release upshift, and a foot return upshift, wherein the target gear ratio setting means includes a shift mode at the time of these upshifts. A speed ratio control device for a continuously variable transmission, wherein the dynamic characteristic is changed in accordance with 2. The shift mode determining means sets an upshift shift mode according to a previous shift mode determination result in addition to the shift ratio deviation, accelerator pedal opening, and input shaft rotational speed change amount. The speed ratio control device for a continuously variable transmission according to claim 1, wherein the shift ratio is determined to be one of an upshift, a foot release upshift, and a foot return upshift. 3. The target gear ratio setting means according to claim 1, wherein said target gear ratio setting means changes said dynamic characteristic based on a dynamic characteristic map set in advance according to each shift mode of an auto upshift, a foot release upshift, and a foot return upshift. The gear ratio control device for a continuously variable transmission according to claim 1, further comprising a characteristic calculating means. 4. The dynamic characteristic calculating means calculates a dynamic characteristic based on the speed ratio deviation.
3. The speed ratio control device for a continuously variable transmission according to claim 1. 5. The target speed ratio setting means, wherein a response speed of the target speed ratio with respect to the attained speed ratio is large during an automatic upshift, low during a return upshift, and automatic upshift when a release upshift is performed. The speed ratio control device for a continuously variable transmission according to claim 1, wherein the speed ratio control device is set to a value between the step-up shift and the foot return upshift.